Bridging die means and method



March 15, 1966 P LONG ETAL 3,240,047

BRIDGING DIE MEANS AND METHOD Filed July 22, 1963 5 Sheets-Sheet 1 FIG-l FIG-2 INVENTORS TH AS P. LONG BYCA M. FILAK x m, 54% I THEIR. ATTORNEYS March 15, 1966 N ETAL 3,240,047

BRIDGING DIE MEANS AND METHOD iled July 22, 1963 5 Sheets-Sheet 5 INVENTO S OMAS R LONG RL M. FILAK THEIR ATTORNEYS March 15, 1966 LONG ETAL 3,240,047

BRIDGING DIE MEANS AND METHOD Filed July 22, 1963 5 Sheets-Sheet 4 INVENTORS THOMAS P. LONG CARL M. FILAK THEIR ATTORNEYS March 15, 1966 T. P. LONG ETAL BRIDGING DIE MEANS AND METHOD 5 Sheets-Sheet 5 FIG-I6 United States Patent 3,240,047 BRIDGING DIE MEANS AND METHOD Thomas P. Long and Carl M. Filak, Chester, Va., as-

signors to Reynolds Metals Company, Richmond, Va., a corporation of Delaware Filed July 22, 1963, Ser. No. 296,678 Claims. (Cl. 72-269) This invention relates to an improved bridging die means for extruding tubular members, pipes or the like and to improved methods for extruding such tubular members, pipes or the like.

It is well known to provide a bridging die means having at least one opening passing through the die means and having a portion of the die means bridging the opening on one side of the die means so that the bridging portion can carry an inner die member disposed in the opening downstream from the bridging portion to cooperate with an outer die member carried by the die means to define a channel therebetween and through which the tubular member can be extruded.

The bridging portion of the die means divides the opening on the one side of the die means into two ports into which extrudable material is forced by a suitable ram or the like to cause the extrudable material to be subsequently welded together into a substantially cylindrical form on opposed sides of the bridging portion before the extruded material is forced through the annular passage defined between the inner and outer die members to produce the tubular member.

Such prior known bridging die means normally comprises one or more such openings passing through the die means so that one or more tubular members can be simultaneously extruded by the bridging die means,

This invention provides improved structure for such a bridging die means as well as improved methods for extruding such tubular members or the like.

In particular, one embodiment of this invention provides a bridging die means wherein at least one die member of each pair of inner and outer die members thereof can be adjusted relative to the other die member of the pair thereof to vary the passage through which the tubular member is to be subsequently extruded.

For example, it has been found that when a bridging die means is formed in the above manner, the inner. die member of each pair of cooperating die members subsequently becomes disposed out of true alignment with its respective outer die member after a certain amount of extrudable material has been initially extruded through the die means because the force of the extrudable material being imposed against the front of the die means varies from the center thereof to the outer periphery thereof whereby the entire die means takes a permanently bowed condition. Accordingly, some means must be provided for compensating for such permanent distortion of the die means.

One means of this invention for compensating for the above described distortion of the die means, is to provide means for adjusting the inner die member of each pair of die members relative to the outer die member without requiring a complete disassembly of the various parts of the die means of this invention.

Another feature of this invention is to provide a die means wherein the material being forced through the ports of the die means is assisted by the ports in the welding action thereof to provide cylindrical configurations on the other sides of the bridging portions of the die means so that the resulting tubular members extruded by the die means of this invention will be substantially homogeneous.

Accordingly, it is an object of this invention to provide 3,240,647 Patented Mar. 15, 1966 "ice an improved bridging die means having one or more of the novel features as set forth above or hereinafter shown or described.

Another object of this invention is to provide an improved method for extruding tubular members or the like, the method of this invention having one or more of the novel features as set forth above or hereinafter shown or described.

Other objects, uses and advantages of this invention are apparent from a reading of this description which proceeds with reference to the accompanying drawings forming a part thereof and wherein:

FIGURE 1 is a rear view of the front part of one of the die means of this invention.

FIGURE 2 is a front view of the front part of the die means of this invention that is illustrated in FIGURE 1.

FIGURE 3 is a cross-sectional view taken substantially on line 33 of FIGURE 1 and illustrates the completed bridging die means of this invention.

FIGURE 4 is a schematic cross-sectional view of the front part of the die means of FIGURE 3 while looking away from the center thereof along line 4-4 of FIG- URE 1.

FIGURE 5 is a view similar to FIGURE 4 while looking into the center of the front part of the die means of FIGURE 3.

FIGURE 6 is an enlarged, fragmentary, cross-sectional view taken on line 66 of FIGURE 3.

FIGURE 7 is an enlarged, fragmentary, cross-sectional view of one of the extruding portions of the die means illustrated in FIGURE 3.

FIGURE 8 is a fragmentary, cross-sectional view taken on line 8-8 of FIGURE 7.

FIGURE 9 is a fragmentary, perspective view of the rear portion of the front part of the die means illustrated in FIGURE 3.

FIGURE 10 is a fragmentary, perspective View of the front part of the die means illustrated in FIGURE 3.

FIGURE 11 is a view similar to FIGURE 1 illustrating the rear of a front part of another bridging die means of this invention.

FIGURE 12 is a cross-sectional view taken on line 1212 of FIGURE 11.

FIGURE 13 is an enlarged, fragmentary, cross-sectional View taken on line 1313 of FIGURE 11.

FIGURE 14 is an enlarged, fragmentary, cross-sectional view taken along line 14-44 of FIGURE 11.

FIGURE 15 is an enlarged, fragmentary, cross-sectional view taken on line 15-15 of FIGURE 11.

FIGURE 16 is a view similar to FIGURE 3 and illustrates the completed bridging die means of FIGURE 11.

FIGURE 17 is a fragmentary, perspective view of the front part of the die means of FIGURE 16.

While the various features of this invention are hereinafter described as being particularly adaptable for forming a bridging die means or the like, it is to be understood that the various features of this invention can be utilized singly or in any combination thereof to provide other types of die means as desired.

Therefore, this invention is not to be limited to only the embodiments illustrated in the drawings, because the drawings are merely utilized to illustrate one of the wide variety of uses of this invention.

Referring now to FIGURE 3, an improved bridging die means of this invention is generally indicated by the reference numeral 20 and is adapted to extrude six tubular members or the like. However, it is to be understood that the various features of the bridging die means 20 of this invention can be utilized to extrude only one or any desired number of tubular members, if desired,

and that this invention is not to be limited to any selected number of tubular members extruded by the claimed invention.

The bridging die means 20 of this invention comprises a front part 21, an intermediate insert plate 22 and a back plate or casing 23 suitably interconnected together by a plurality of bolt means 24 and 25 or any other suitable fastening means.

The parts 21-23 of the die means 20 are so constructed and arranged that a plurality of openings 26 pass completely through the die means 20' from the side 27 thereof to the side 23 thereof. However, the front part 21 of the die means 20 has a plurality of portions 29, FIGURES 2 and 3, bridging the openings 26 at the side 28 of the die means 20 to divide each opening 26 into a pair of ports 30 respectively leading around the respective bridging portion 29 to the part 31 of the opening 26 disposed downstream from the respective bridging portion 29 in the manner illustrated in FIGURE 4.

As fully illustrated in FIGURES 9 and 10, each bridging portion 29 of the front part 21 of the die means 20 comprises a pair of frusto-conical portions 32 and 33 integrally joined together at the larger ends thereof to be substantially concentric with the opening 26. However, web-like portions 34 and 35 respectively extend from opposed sides of the respective conical portions 32 and 33 to be joined integrally with the side walls defining the respective openings 26 to complete the bridging portions 29 in the manner illustrated in FIGURES 9 and 10, the reinforcing part 35 of each bridging portion 29 extending upwardly to a central part 36 of the die means 20 as illustrated in FIGURE 3.

As illustrated in FIGURE 10, each pair of ports 30 leading around a respective bridging portion 29 to the part 31 of the respective opening 26 is substantially kidneyshaped and is adapted to convey a greater quantity of extrudable material to the portion 31 of the opening 26 at a point disposed the greatest radial distance from the center 36 of the die means 20 than the quantity of material conveyed thereby to portions of the part 31 of the opening 26 disposed closer to the center 36 of the die means 20 for a purpose hereinafter described.

The adjacent ports 30 of adjacent bridging portions 29 as illustrated in FIGURES 2, 4 and are so constructed and arranged that the same are substantially arcuate in cross section to assist the action of the extrudable material passing therethrough to be divided into two parts to be readily welded in the portions 31 of the openings 26 at a point beyond the respective bridging portions 29 to form substantially cylinderical portions.

Further, the adjacent ports 30 of adjacent bridging portions 29 are so constructed and arranged that the same define a substantially tapering portion 37 as illustrated in FIGURES 2, 4, 5 and to tend to divide the extrudable material being pushed against the front side 28 of the die means into adjacent portions passing into the adjacent ports 30 in a manner hereinafter described.

Each bridging portion 29 has a bore 38 passing centrally therethrough in the manner illustrated in FIGURE 7, the bore 38 having an outwardly tapering portion 39 at the leading end thereof.

A pin-like member or mandrel 40 is disposed in each bore 38 of the bridging portions 29 and has a frustoconical portion 41 received in the tapering portion 39 of the bore 38 in the manner illustrated in FIGURE 7 whereby the f-rusto-conical portion 41 of the pin-like member 40 limits the degree of insertion of the pin-like member 40 to the left from the position illustrated in FIGURE 7.

The pin-like member 40 has a substantially cylindrical portion 42 disposed in the cylindrical bore 38 of the respective bridging portion 29 and has an eccentric portion 43 extending beyond the flat end 44 of the respective bridging portion 29 in the manner illustrated in FIG- URE 7.

A frusto-conical, washer-like member 45 is disposed on each eccentric portion 43 of each pin-like member 40 and has an outer peripheral surface 4-6 substantially complementary to the conical portion 33 of the respective bridging portion 29 and is adapted to space an inner carbide die member 47 or the like disposed on the eccentric portion 43 of the pin-like member 40 from the end 44 thereof in the manner illustrated in FIGURE 7.

The outer end 48 of each pin-like member 40 is externally threaded and threadedly receives a threaded nut 49 or the like in the manner illustrated in FIGURE 7 whereby tightening of the nut 47 on the threaded portion 48 of the pin-like member 40 not only tightly draws the fr usto-conical portion 41 of the pin-like member against the tapering portion 39 of the bore 38 but also compacts the inner die member 47 and washer 45 against the end 44 of the respective bridging portion 29.

The other end 50 of each pin-like member 40 is provided with a hexagonal part or the like to readily permit a wrench or other suitable tool to grasp the same to rotate the pin-like member 40, when desired.

For example, the nut 49 can be loosened on the end 48 of the respective pin-like member 40 and the pinlike member 40 can be rotated relative to the respective bridging portion 29 by the end 50 thereof whereby theeccentric portion 43 is adapted to vary the position of the inner die member 47 relative to the respective opening 26 for a purpose hereinafter described.

The intermediate insert carrier 22 of the die means 20 has a plurality of stepped bores 51 at the bores 26 thereof, each bore 51 defining a pair of annular shoulders 52 and 53 for a purpose hereinafter described. Each annular shoulder 53 forms the end surface of a tapering part 54 of the bore thereof which is substantially aligned with the tapering portions 37 of the front part 21 of the die means 20 in the manner illustrated in FIGURE 7.

A steel insert 55 is adapted to be disposed in each stepped bore 51 of the intermediate plate 22 and has an end surface 56 thereof disposed against the shoulder 52 of the plate 22, each steel insert 55 carrying a carbide outer die member 57 or the like which is adapted to project beyond the end surface 56 of the steel insert 55 and be disposed against the shoulder 53 of the plate 22.

Each inner die member 57 has an inner surface 58 disposed inboard of the inner portion of the shoulder 53 of the plate 22 to cooperate with the inner die member 47 to define an annular passage 59 therebetween through which a tubular member 60 is adapted to be extruded in a manner hereinafter described.

The steel insert 55 is relieved at 61 so that the outer die member 57 will be squeezed substantially uniformly by the steel insert 55 in a manner hereinafter described.

Each outer die member 57 has the inner corner 61 thereof slightly chamfered to facilitate the extruding operation on the tubular member 60 in the passage 59 between the die members 47 and 57.

When the outer carbide die members 57 are mounted in the steel holders 55 for a subsequent hot extrusion by the die means 20 in a manner hereinafter described, it is necessary to allow for differences in coefficient of thermal expansion between the carbide die members 57 and the steel inserts 55.

Also, the carbide die members 57 must have a minimum of 0.001/ 0.002 per inch interference fit at extrusion temperature which is normally expected to be approximately 1,000 F.

The difference of thermal expansion between the steel insert 55 and the die members 57 will average about 0.004 per inch per 1,000 F. Thus, a carbide die member 57 of one inch in diameter would measure approximately 1002+ at 1,000 F. while a steel insert 55 that is 0.995 of an inch in diameter would measure approximately 0001+ at 1,000 F. This combination will give the 0.001 per inch interference fit as required.

Normally, each inner outer die member 57 to be assembled to a respective steel insert 55 will have to be at room temperature while the steel insert 55 has been pre-heated to 1,l00 F. maximum temperature.

In regard to the inner carbide die members 47 being mounted on the eccentric portions 43 of the mandrel or pin-like members 40, such tolerances are computed in the same fashion as set forth above except that the fits have to be reversed as the carbide die member 47 cannot have more than 0.002 per inch per 1,000 F. interference. Thus, the pin-like member 40 being one inch in diameter would measure approximately 1.006+ inches at 1,000 P. while the carbide die member 47 having a 1.003 inch inside diameter would measure 1.007 inches at 1,000 F.

After the inserts 55' and their respective outer die members 57 have been placed in the insert plate 22 in the above manner, the back-up plate 23 is placed thereagainst wherein the front surface 63' of the backup plate 23 compacts the inner die members 57 against the shoulders 53 of the insert carrier 22 in the manner illustrated in FIG- URE 7 to complete the assembly of the die means 20 of this invention.

The operation of the die means 20 will now be described.

Assuming that the die means 20 has been formed in the above manner and that the pin-like members 40 have been adjusted in the manner set forth above to properly position the inner die members 47 relative to the outer die members 57, the die members 47 and 57 will initially provide the tubular members 60 in a substantially uniform manner.

In particular, billets of hot extrudable material, such as aluminum-containing metallic material or the like, are rammed against the side 28 of the die means 20 to cause the extrudable material to respectively enter the ports 30 of the die means 20 and subsequently reach the portions 31 of the openings 26 disposed beyond the bridging portions 29 and before the cooperating pairs of die means 47 and 57 whereby the separate portions of the extrudable material passing around each side of each bridging portion 29 will weld together in the portion 31 of the respective opening 26 to provide a substantially cylindrical mass of material ready to enter the passage 59 between the cooperating die means 47 and 57.

As the extrudable material is forced through the passages 59 of the die members 47 and 57, the same forms tubular members 60 in the manner illustrated in FIGURE 7 whereby the tubular members 60 are continuously extruded through the openings 26 of the die means 20 and pass beyond the side 27 thereof so that the same can be cut to the desired lengths by any suitable apparatus.

Since the ports 30 are substantially arcuate in cross section and are substantially kidney-shaped, the same tend to cause the extrudable material entering the same to readily form into cylindrical forms beyond the bridging portions 29 in the manner previously described while the tapering portions 37 of the die means 20 readily permits the extrudable material to divide into adjacent ports 3% of adjacent bridging portions 29 thereof.

Since the ports 30 are so constructed and arranged that the same tend to deliver a greater quantity of material at the farthest radial points from the center 36 of the die means 20, the excess material at the farthest radial portions of the bridging die means 20 tends to compensate for the increased forces provided at the closest radial distances from the center of the die means 36 acting against the die members 47 and 57 whereby the amount of material being delivered to each part 31 of the openings 26 of the die means 20 tends to hold the uniformity between the die members 47 and 57 without bending the pin-like members 40.

However, it has been found that when the die means 20 is initially utilized in the above manner, the same tends to bow from the center 36 thereof to the outer peripheral portions thereof because the greater force is being applied by the extrudable material against the center 36 thereof than at the outer peripheral portions thereof whereby after a certain quantity of material has been initially extruded by the die means 20, the die means 20 tends to take a permanent set in its bowed condition whereby the inner die members 47 are out of true alignment with the outer die members 57 so that the subsequently formed tubular members 60 are not uniform.

In the past, such die means had to be disassembled and adjustments made for this bowed condition of the bridging die means.

However, according to the teachings of this invention. each pin-like member 40 can be rotated relative to its bridging portion 29 in the manner previously described whereby, through the eccentric 43 of each pin-like member 40, the inner die member 47 can be adjusted relative to its outer die member 57 to vary the passage 59 to compensate for the permanently bowed condition of the die means 20 in a relatively simple manner whereby the die means 20 can be continued to be operated in the above manner to continuously produce the tubular members 60.

Therefore, it can be seen that not only does the die means of this invention provide unique means for extruding the tubular members 60, but the same permits ready adjustment of one of each pair of die members 47 and 57 thereof to compensate for a permanently bowed condition of the die means 20 after the same has been initially utilized in the above manner or for other purposes, as desired.

Another bridging die means of this invention is generally indicated by the reference numeral 63 in FIG- URES 11l7 and parts thereof similar to the die means 20 previously described are indicated by like parts followed by the reference letter A.

In particular, the die means 63 is substantially the same as the die means 20 previously described except that the front part 21A of the die means 63 has been modified over the part 21 of the die means 20 previously described.

In particular, the front part 21A of the die means 63 has a substantially annular opening 64 provided in the side 28A thereof which joins with the aligned openings 26A formed in the back-up plate 23A and intermediate insert carrier 22A.

In particular, the annular opening 64 formed in the front part 21A of the die means 63 has a plurality of bridging portions 29A spanning the same to divide the annular opening 64 into a plurality of ports 65, each port 65 respectively leading to two openings 26A as each port 65 is not divided into two parts by a tapering portion of the part 21A in the manner provided by the tapering portion 37 of the die means 20 previously described.

For example, each bridging portion 29A includes a central portion defined by a pair of frusto-conical portions 32A and 33A respectively joined together at the larger ends thereof and to the remainder of the part 21A by reinforcing web portions 34A and 35A as illustrated respectively in FIGURES 13 and l5.

Each bridging portion 29A of the die means 63 is adapted to carry an inner die member 47A in the manner previously described by a mandrel or pin-like member A in the manner previously described for the purpose previously described.

'However, each pin-like member 40A of the die means 63 is not provided with the frusto-conical portion 41 previously described and the enlarged end A of the pinlike member is received in a bore 66 formed in the part 21A in the manner illustrated in FIGURE 16.

However, each pin-like member 40A is adapted to operate in the same manner as the pin-like members 40 previously described to adjust the position of the inner die members 47A relative to the outer die members 57A in the manner previously described and for the purposes previously described.

Each port 65 of the die means 63 is defined in part by a peripheral portion 67 of the part 21A in such a manner that each peripheral portion 67 is substantially scalloped to define two arcuate portions 68 separated from each other by an intermediate inwardly directed portion 69 in the manner illustrated in FIGURES 11 and 17.

It has been found that by so scalloping the peripheral portions 67 of the part 21A that defines the ports 65, the same assists the action of the extrudable material passing through the die means 63 to weld together and form homogeneous cylindrical portions in the parts 31A of the openings 26A disposed beyond the bridging portions 29A and before the cooperating die members 47A and 57A in the manner previously described.

The operation of the die means 63 of this invention will now be described.

When the extrudable material is forced against the sides 28A of the die means 63 by any suitable ram, the same is forced into the ports 65 and is subsequently received in the portion 31A of the openings 26A beyond the bridging portions 29A and before the die means 47A and 57A whereby the extruding material passing through the ports 65 on opposite sides of a particular bridging portion 2A weld together in such portions 31A of the openings 26A to provide a substantially, homogeneous cylindrical mass.

However, because of the scalloped portions 68 formed in the die part 21A, the material passing through the ports 65 tend to curl in the proper direction to readily form the cylindrical mass on the other side of the bridging portions 29A in much the same manner as produced by the kidney-shaped ports 30 of the die means 20 previously described.-

Thereafter, the extrudable material passes through the passages 59A defined between the cooperating die members 47A and 57A to form the tubular members 60 in the manner previously described.

Therefore, it can be seen that the die means 63 operate in substantially the same manner as the die means 20 previously described and the inner die members 47A thereof are adapted to be adjusted relative to the outer die members 57A thereof in a manner previously described by merely rotating the pin-like members 40A when desired.

Although the term bridging dies has been used to describe this invention, the terms bridge dies and porthole dies are equally applicable.

Accordingly, it can be seen that this invention not only provides improved bridging die means for extruding tubular members, pipes or the like, but this invention also provides an improved method for extruding such tubular members, pipes or the like.

While the form of the invention now preferred has been disclosed as required by the statutes, other forms may be used, all coming within the scope of the claims which follow.

What is claimed is:

1. In a bridging die means or the like for extruding a tubular member or the like, said die means having a bridging portion provided with a cylindrical bore, a rotatable pin carried by said die means and having an eccentric portion and a cylindrical portion, said cylindrical portion being disposed in said bore with said eccentric portion extending beyond said bridging portion whereby said pin rotates about the longitudinal axis of said cylindrical portion thereof and the coinciding longitudinal axis of said bore, an inner die member telescoped on said eccentric portion, and means carrying an outer die member which cooperates with said inner die member to define a passage through which said tubular member is formed whereby rotation of said pin adjusts the position of said inner die member relative to said outer die member to vary said passage.

2. A bridging die means or the like for extruding a tubular member or the like, said die means having an opening passing therethrough, said die means having a portion bridging said opening on one side of said die means to define two ports leading to said opening at the other side of said die means and having a cylindrical bore, an inner die member carried by said bridging portion and disposed in said opening beyond said ports and said bridging portion, I311 outer die member carried by said die means and co'operable with said inner die member to define a passage through which said tubular member is formed as a mass of extrudable material is forced against said one side of said die means and through said ports to said opening beyond said die members, and means for adjusting the position of said inner die member relative to the other die member, said adjusting means including a rotatable pin having an eccentric portion extending beyond said bridging portion and la cylindrical portion received in said cylindrical bore, said inner die member being telescoped on said eccentric portion whereby said inner die member is adjusted relative to said outer die member when said pin is rotated about the longitudinal axis of said cylindrical portion thereof and the coinciding longitudinal axis of said bore.

3. A bridging die means or the like as set forth in claim 2 wherein another opening is provided in said die means and has a portion bridging the same on one side of said die means to define two ports leading to said last-named opening.

4. A bridging die means or the like as set forth in claim 3 wherein one port of said last-named opening and one port of said first-named opening are separated from each other by a portion of said die means that tapers toward said one side of said die means.

5. A bridging die means or the like as set forth in claim 4 wherein said last-named portion has a relatively sharp leading edge to assist in dividing said mass of material to flow into said adjacent ports.

6. A bridging die means or the like as set forth in claim 3 wherein said one port of said last-named opening and said one port of said first-named opening are the same.

'7. A bridging die means or the like as set forth in claim 6 wherein said die means has a pair of scalloped portions at said last-named ports to tend to divide the mass of material entering said last-named ports into two portions leading to said openings in a manner to facilitate the welding together of the mass of material beyond each bridging portion.

8. A bridging die means 'or the like for extruding a tubular member or the like, said die means having an opening passing therethrough, said opening having a portion bridging said opening on one side of said die means to define two ports leading to said opening at the other side of said die means, each port being arcuate in cross section, an inner die member carried by said bridging portion and disposed in said opening beyond said ports, and an outer die member carried by said die means and cooperable with said inner die member to define a passage through which said tubular member is formed as a mass of extruda'ble material is forced against said one side of said die means and through said ports to said opening beyond said die members, said arcuate ports facilitating Welding together of the two portions of said mass of material that passes through said ports beyond said bridging portion, said die means having another opening having a portion bridging the same on one side :of said die means to define two ports leading to said last-named opening at the other side of said die means.

9. A bridging die means or the like as set forth in claim 8 wherein one port of said last-named opening and one port of said first-named opening are separated from each other by a portion of said die means.

10. A bridging die means or the like as set forth in claim 9 wherein said last-named portion has a relatively sharp leading edge to assist in dividing said mass of material to flow into said adjacent ports.

11. A bridging die means or the like for extruding a tubular member or the like, said die means having a first opening interrupting one side thereof and second and third openings interrupting the other side thereof and interconnected to said first opening, said die means having a pair of portions bridging said first opening to define three ports whereby one outer port and the middle port lead to said second openings and the other outer port and said middle port lead to said third opening, a pair of inner die members respectively carried by said bridging portions and disposed in said second and third openings, a pair of outer die members carried by said die means and cooperating with said inner die members to define passages through which said tubular members are formed as a mass of extrudable material is forced against said one side of said die means and through said ports to said second and third openings beyond said die members.

12. A bridging die means or the like as set forth in claim 11 wherein said die means has a portion defining part of said middle port that has two adjacent scalloped sections that tend to divide the mass of material entering said middle port into two portions leading to said second and third openings in a manner to facilitate the welding together of the mass of material beyond each bridging portion.

'13. A bridging die means or the like for extruding a tubular member or the like, said die means having an opening passing thereth-rough, said die means having a portion bridging said opening on one side of said die means to define two ports leading to said opening at the other side of said die means, a rotatable pin carried by said bridging portion and having an eccentric portion disposed in said opening beyond said ports, an inner die member carried by said eccentric portion, and an outer die member carried by said die means and cooperable with said inner die means to define a passage through which said tubular member is formed as a mass of extrudable material is forced against said one side of said die means and through said ports to said opening beyond said die members whereby rotation of said pin adjusts the position of said inner die member relative to said outer die member to vary said passage, said pin having an enlarged head engaging one side of said bridging portion and a nut-like member engaging said inner die member whereby said nut-like member cooperates with said enlarged head to compact said inner die member against said bridging portion.

14. A bridging die means or the like for extruding a tubular member or the like, said die means having an opening passing therethrough, said opening having :a portion bridging said opening on one side of said die means to define two ports leading to said opening at the other side of said die means, each port being kidney shaped and having the concave side thereof facing the concave side of the other port, an inner die member carried by said bridging portion and disposed in said opening beyond said ports, and an outer die member carried by said die means and cooperable with said inner die member to define a passage through which said tubular member is formed as a mass of extrudable material is forced against said one side of said die means and through said ports to said opening beyond said die members, said ports facilitating the welding together of the two portions of said mass of material that passes through said ports beyond said bridging portion, said opening being offset relative to the center of said die means and said ports conveying a greater quantity of said material to said opening upstream of said die members at the greatest radial distance from the center of said die means than the amount of material conveyed thereby to points closer to the center of said die means.

15. A bridging die means or the like for extruding a tubular member or the like, said die means having an opening passing therethrough, said die means having a portion bridging said opening on one side of said die means to define two ports leading to said opening at the other side of said die means, an inner die member carried by said bridging portion and disposed in said opening beyond said ports, an outer die member carried by said die means and cooperable with said inner die member to define a passage through which said tubular member is formed as a mass of extrudable material is forced against said one side of said die means and through said ports to said opening beyond said die members, and means for adjusting the position of said inner die member relative to the other die member, said adjusting means comprising a rotatable pin carried by said die means and having an eccentric portion telescoped in said inner die member, said opening being offset relative to the center of said die means and said ports conveying a greater quantity of material to said opening upstream of said die members at the greatest radial distance from the center of said die means than the amount of material conveyed thereby to points :closer to the center of said die means.

References Cited by the Examiner UNITED STATES PATENTS 262,028 8/1882 Farrell 20717.4

450,175 8/1891 M-athcett 20717.4 1,185,302 5/1916 Garretson 207--18 1,983,761 12/1934 Jacobson 207-17.4 2,073,465 3/1937 Deitz 207-17.4 2,181,987 12/1939 Beaver et al. 207-4 2,266,189 12/1941 Ganoe 20717 2,276,468 3/1942 Couchman 207-17 2,973,092 2/1961 Graham 207-17 FOREIGN PATENTS 184,028 4/ 1955 Austria.

CHARLES L. LANHAM, Primary Examiner. 

1. IN A BRIDGING DIE MEANS OR THE LIKE FOR EXTENDING A TUBULAR MEMBER OR THE LIKE, SAID DIE MEANS HAVING A BRIDGING PORTION PROVIDED WITH A CYLINDRICAL BORE, A ROTATABLE PIN CARRIED BY SAID DIE MEANS AND HAVING AN ECCENTRIC PORTION AND A CYLINDRICAL PORTION, SAID CYLINDRICAL PORTION BEING DISPOSED IN SAID BORE WITH SAID ECCENTRIC PORTION EXTENDING BEYOND SAID BRIDGING PORTION WHEREBY SAID PIN ROTATES ABOUT THE LONGITUDINAL AXIS OF SAID CYLINDRICAL PORTION THEREOF AND THE COINCIDING LONGITUDINAL AXIS OF SAID BORE, AN INNER DIE MEMBER TELESCOPED 